What is the management of pacemaker-induced cardiomyopathy?

Management of Pacemaker-Induced Cardiomyopathy

Upgrading to cardiac resynchronization therapy (CRT) is the first-line treatment for pacemaker-induced cardiomyopathy (PiCM) to improve left ventricular function and reduce heart failure symptoms. 1

Definition and Diagnosis

• PiCM is defined as a reduction in left ventricular ejection fraction (LVEF) to <50% with a ≥10% decrease from baseline in the setting of chronic, high-burden right ventricular (RV) pacing, without alternative causes of cardiomyopathy 1, 2
• Prevalence is approximately 12% among patients with chronic RV pacing 2
• Key risk factors include:
  • Male sex
  • Longer paced QRS duration (≥150 ms is 95% sensitive for PiCM) 3
  • Higher RV pacing percentage (≥20%)
  • History of myocardial infarction
  • Chronic kidney disease
  • Atrial fibrillation 2

Management Algorithm

1. Device Therapy (Primary Intervention)

• First-line: Upgrade to CRT for patients with PiCM, especially those with:

  • LVEF ≤35%
  • QRS duration ≥130 ms
  • NYHA class II-IV symptoms 1

• Alternative: Conduction system pacing

  • His bundle pacing or left bundle branch pacing may be considered as alternatives to CRT 1, 4
  • These approaches may provide more physiological ventricular activation

2. Medical Therapy (Concurrent Management)

• Implement standard heart failure medications:
  • ACE inhibitors or ARBs
  • Beta-blockers
  • Mineralocorticoid receptor antagonists
  • Diuretics for symptom management 1

3. Timing of Intervention

• Implement upgrade to CRT as soon as PiCM is diagnosed 5
• Consider earlier intervention before severe LV dysfunction develops, particularly in high-risk patients 1
• Most improvement occurs within the first 3 months after CRT upgrade, though improvement may continue throughout the first year 6

Expected Outcomes

• After CRT upgrade, LVEF typically improves significantly:
  • Average improvement from 29.3% to 45.3% over a median of 7 months 6
  • Approximately 72% of patients with severe PiCM (LVEF ≤35%) improve to LVEF >35% 6
  • LV end-diastolic dimensions decrease and BNP levels typically improve 5

Important Clinical Considerations

• Early detection is crucial: About half of patients with PiCM have no heart failure symptoms at the time of echocardiographic diagnosis 3
• Screening recommendation: Patients with frequent RV pacing (≥20%) and paced QRS duration ≥150 ms should undergo echocardiographic screening for PiCM, even in the absence of symptoms 3
• Non-responders: Approximately 24% of patients may not respond to CRT upgrade 5
• Predictors of response: Narrower native QRS duration is associated with greater LVEF improvement following CRT upgrade 6
• Consider staged approach: For severe PiCM cases, consider initial upgrade to CRT pacemaker with potential further upgrade to CRT defibrillator after 1 year if LVEF remains ≤35% 6

Prevention Strategies

• Minimize unnecessary RV pacing when possible
• Consider His bundle pacing or left bundle branch pacing as initial pacing strategy in patients requiring high percentage of ventricular pacing 4
• Regular echocardiographic monitoring in high-risk patients with frequent RV pacing